Automobile couplings for transferring fluid are being improved since they can enable the time required for assembly on a production line to be reduced, thereby achieving savings for the manufacturer, in particular for transferring air (filtering, turbocharging, exhaust gas recycling (EGR), etc.). These functions require leaktight couplings under the engine hood for transferring fluids between a feed pipe presenting an endpiece and a connecting tube of the engine.
Coupling manufacturers seek to provide these components using technologies that are inexpensive and that require little space. They therefore generally make parts that are rolled, and that have large radii of curvature in the bottoms of grooves for receiving sealing gaskets.
When the dimensions of a coupling are large, the O-rings presently in use require high assembly forces to be applied, so manufacturing costs are not economical.
Furthermore, lip gaskets are not suitable for fluid transfer couplings presenting large radii of curvature. In addition, the cost of a lip gasket is generally high and such a gasket is asymmetrical: it must be put into place in a particular direction and the risks of failure are not negligible.
There also exist four-lobe gaskets. These gaskets do not enable the lobes to be sufficiently compressed in the bottom of the groove when the lobes are dimensioned for a groove having a given size of opening, it being understood that the bottom of the groove is necessarily narrower than its opening. Thus, such gaskets do not enable coupling to be achieved merely by deforming the outer lobes, nor can they accommodate sufficient variety of dimensional tolerances in the bottoms of grooves. Thus, such gaskets require a significant increase in axial assembly forces.